“They don’t trump each other,” Josh Levine, cofounder and chief creative officer at e-commerce design firm Alexander Interactive, told conference attendees. “If one side is winning the other is losing. You’ve got to find the balance.”

With visitors so easily able to jump to competitors’ sites, the e-commerce sites that don’t make it easy for consumers to navigate, search and buy don’t survive, Levine said. At the same time, how the site looks—based on design choices—delivers a powerful emotional appeal to engage customers that a plain but functional site does not.

Levine, whose background is in graphic design, noted that even e-commerce sites heavily focused on usability and not usually associated with aesthetics, such as Amazon and eBay, aren’t sacrificing form to function in recent redesigns.

Usability requirements may be tied to business objectives for an e-commerce site, such as, in a recent redesign of Saks Fifth Avenue’s site, the need to modernize the design, align the site more closely with other brand visuals, and maximize site real estate. It’s design’s job to meet such requirements by the proper application of such principles as balance, unity and contrast to site design elements such as color, type and imagery, Levine said.

With co-presenter Jordan Lustig, director of product management at Saks Inc., No. 38 in the Internet Retailer Top 500 Guide, Levine shared examples of how Saks and Alexander Interactive balanced design aesthetics with usability and its underlying business goals in redesigning Saksfithavenue.com.

By corporate directive, Saks’ visual branding graphics, such as its logo, use only the colors black and white, Levine said. Yet black is one of the most difficult colors to incorporate successfully into web design, he added. A redesign of the site’s top navigation bar incorporated some gray in a compromise.

The category refinement feature was another point of contention between design aesthetics and usability. “Every designer I worked with wanted to get rid of category refinement,” Lustig said. Levine and his team had initially removed that component to gain what they considered a cleaner, simpler look. But Lustig and his team explained that there was a solid business reason for keeping it in place. “We stood our ground. We said users who use it convert higher,” Lustig said. The feature stayed.

Levine and Lustig offered advice on how to reduce friction between the competing demands of usability and design aesthetics in the site redesign process. Before starting, designers, marketers and any others involved should define roles, ownership and business requirements. Reviewing analytic data on the site and its visitors also helps settle disputes over direction, as does identifying the measures that will define success, they said.

“Design is having an effect on your customers whether you are consciously aware of it or not,” Levine said. “Easy to use isn’t good enough. Design is what differentiates.”